Michelle Darmody: How to bake perfect zesty lemon slices

Homemade Lemon Bars on a Cooling Rack

There squishy, zesty squares are an extremely popular treat. With their lightly crisp base and soft curdy topping they are both lush and beautifully flavoursome.

They are also deceptively rich, so you might find that dividing the tray into nine gives you slices that are a little too big for you or your guests. You can cut them much smaller if you wish.

Baking a batch of the slices is a nice way to while away a few hours on a weekend and it has the bonus of having the smell of lemony baking wafting through the house.

This recipe does have a knack to it. I shared it here a few years ago and I think it elicited more comments and feedback from readers than any other baking recipe.

Readers who really enjoyed making (and eating) the tangy slices got in touch, and many had questions about perfecting the recipe.

I hope today’s column answers those questions for all aspiring lemon slice bakers. The main topic of discussion was that the topping turned out a little more like a meringue than curd.

This will happen if the topping mixture is whisked too much, and an excess of air bubbles are added.

You just need to whip the topping gently until it has doubled in volume.

This and other tips and tricks are included below to help you make the perfect lemon slices.

Lemon slices

recipe by:Michelle Darmody

They are also deceptively rich, so you might find that dividing the tray into nine gives you slices that are a little too big for you or your guests. You can cut them much smaller if you wish.

Servings

9

Preparation Time

 20 mins

Cooking Time

 20 mins

Total Time

 40 mins

Course

 Baking

Ingredients

• For the base:

• 250g plain flour

• 100g icing sugar

• Zest 1 lemon

• A pinch fine sea salt

• 250g cold butter, cubed

• For the topping:

• 4 eggs

• Zest 2 lemons

• A pinch fine sea salt

• 300g caster sugar

• 100ml lemon juice

• 1 level tsp baking powder, sieved

• 50g plain flour, sieved

Method

1. Line a 9-inch square tin with parchment and preheat your oven to 180ºC/gas mark 4.

2. Mix the flour, sugar, zest, and salt. Rub the butter into the mixture until it looks like rough breadcrumbs. Scoop the mixture into your tin and pat in down well, so that it is flat and even all over.

3. Bake for 20 minutes until it is lightly golden. Remove the tray from the oven and allow the base to cool to room temperature.

4. To make the topping: beat the eggs, zest, salt, and sugar until doubled in volume. It should not have any peaks but just be starting to become slightly foamy. Stir in the lemon juice, baking powder, and flour.

5. Scoop this mixture onto your cooled base and bake for about 20 minutes at 180ºC/gas mark 4. After this time if it still wobbles a lot in the centre leave it in for another few minutes.

6. Allow to cool in the tin and slice with a knife dipped in hot water.

Baker's secrets

Ensuring just the right amount of baking time for the topping is the knack that I mentioned. One of the most likely things to go wrong is a runny top. If there is still a pronounced wobble in the centre bake the slices for another one or two minutes.

The parchment paper around the base stops the topping from leaking down the sides or in under the biscuity base. Make sure after baking the crust that you do not detach the parchment paper from its edges because moving the paper will create a gap where the filling will leak into.

To prevent a soggy base, be sure to leave it cool to room temperature before adding the topping.

Use cold butter straight from the fridge to give a crisp result. Cutting the cold butter into small cubes allows you to incorporate it with the other ingredients quickly and allows the butter to stay solid rather than become oily.

If the surface of the slices cracks, they are over-baked. The slices are ready to take out of the oven when the edges are just set, and the filling is a little wobbly but is not liquid. It will continue to set as it cools down.

Over-beating the topping will result in a meringue effect rather than the curdy texture you are looking for; you want the top to be nice and smooth like a set lemon curd. The mixture should just double in volume and not have any peaks when you lift the whisk from the mixture.

Bottled lemon juice will not taste as tangy as fresh lemons.

The lemon slices are best served at room temperature, as the centre will be moist gooey, and the crust will be crisp.

Three delicious variations

Lime & chocolate slices

Replace the lemon zest in the base with lime zest. Replace 30g of flour with 30g of cocoa powder. Otherwise follow the recipe for the base as is. For the topping use 100mls of lime juice and the zest of 4 limes in place of the lemon juice and zest.

Raspberry & lemon slices

To make a beautiful pink version use 80mls of raspberry purée in place of 80mls of lemon juice. I stew either fresh or frozen raspberries and push them through a sieve to make a purée. Don’t add any sugar when you are stewing them.

Gluten-free lemon slices

For a gluten-free version substitute the plain flour with gluten-free flour and be careful to remove any ingredients that contain gluten from your vicinity as you bake. You will need to make sure your baking powder is gluten-free as well. Most brands are typically gluten-free by default, but it is always worth double checking.